1. Field of the Invention
This invention relates to a single-loop, Rankine-cycle power unit and, more particularly, to such a power unit which employs a supersonic condenser-radiator and is especially adapted to space application.
2. Description of the Prior Art
A power unit which has been designed for use in space applications is a closed Brayton cycle unit with a pair of heat exchangers and a heat radiator as shown in FIG. 1. A heat source heats the primary working fluid (e.g., a He mixture) in a heat exchanger before the fluid is fed to a turbine. The exhaust gas from the turbine is then cooled down in a second heat exchanger before being fed to a compressor to raise its pressure. A second working fluid (e.g., Dow 705) is pumped through the second heat exchanger where it absorbs heat from the first working fluid and is then passed through a liquid droplet radiator (or other type radiator) which removes its heat energy. The problem with this arrangement is that a very large second heat exchanger and fluid system is required. This unit is bulky, heavy and, because of its size, subject to meteorite damage and possible failure by leakages over a 20-year cyclic life period in space.